Direct injection alcohol engine with boost and spark control

ABSTRACT

Boosted engine operation and spark timing of an engine may be adjusted with alcohol content of the fuel in a direct injection engine. Further, various adjustments may be performed in numerous related systems to account for increased maximum engine torque, such as traction control, transmission shifting, etc.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/464,172 filed Aug. 11, 2006, now U.S. Pat. No. 7,909,019,the entire contents of which are incorporated herein by reference.

BACKGROUND AND SUMMARY

Various fuels have been identified to mitigate the rising price ofenergy and environmental concerns. For example, alcohol has beenrecognized as an attractive alternative source of energy, and moreparticularly a fuel for automotive applications. Various engine systemsmay be used with alcohol fuels, utilizing various engine technologiessuch as turbo-chargers, super-chargers, etc. Further, various approachesmay be used to control alcohol-fuelled engines with such devices,including adjustment of boost or spark timing in dependence upon analcohol content of the engine fuel, and various operating conditions.

The inventors herein have recognized several interrelated issues withalcohol-fuelled engines involving the fuel delivery system, and foundthat it is possible to operate the engine system to achieve improvedengine performance with an alcohol fuel or blend by varying the amounts,timing, and number of injections.

In one example, an engine system is provided for an engine having atleast a cylinder and combusting a fuel, the system comprising: a directinjection fuel injector coupled to the cylinder; an intake chargeboosting device coupled to the engine and fluidly coupled to thecylinder; and a control system for varying at least a spark timing ofthe cylinder and boost amount of said device as an alcohol content ofthe directly injected fuel varies, said system operating the engine toproduce increased peak torque output when said alcohol content isincreased, at least during one condition.

In this way, it is possible to utilize direct injection and boosting,along with an appropriate boost, spark, and fuel control system, to takeadvantage of increased charge cooling effects via alcohol's increasedheat of vaporization and increased octane to provide an engine withimproved peak torque output. In one particular example, peak enginetorque, at least for some conditions, can be increased when using a fuelwith increased alcohol compared to another fuel with less alcoholcontent. Such performance can be achieved using the above approach, eventhough the fuel with increased alcohol may have a reduced energydensity.

As such, a customer can be encouraged, rather than discouraged, toutilize alternative fuels as such use can proved improved engineperformance. The improved performance can provide various benefits, suchas improved towing capacity, improved acceleration, and/or variousothers.

Further, use of such alternative fuels may also provide reducedemissions and various other environmental and/or economic advantages.For example, use of direct injection fuel can reduce the effect ofvarying amounts of alcohol on intake system puddling. The improvedair-fuel ratio control can then be used to further reduce the likelihoodof knock by providing more appropriate spark timing.

In another aspect, improved marketing and/or advertising may beachieved. For example, it may be possible to inform potential consumersthat a vehicle having an engine (with one or more of the featuresdescribed herein) may be able to obtain improved vehicle performancewhen using a fuel with increased alcohol, rather than simply maintainingperformance or achieving degraded performance.

DESCRIPTION OF DRAWINGS

FIG. 1 shows a generic engine system;

FIG. 2 shows a partial engine view;

FIG. 3 shows an engine with a turbocharger;

FIG. 4 shows example fuel tank and pump configurations;

FIG. 5A shows a routine for adjusting fuel injection parameters takinginto account an amount of alcohol in the fuel system;

FIG. 5B shows various examples of variable injection timing and numberof injections per cycle;

FIG. 6 shows a flow chart illustrating the process sequence of theengine;

FIG. 7 shows a flow chart schematically showing how the operatingparameters are determined;

FIG. 8 shows a process control flow chart illustrating how thetransmission and cooling system are governed by torque, speed, and thepedal position;

FIGS. 9-10 show flow charts outlining an example advertising andmarketing strategy to sell a vehicle with various engine features.

DETAILED DESCRIPTION

FIG. 1 shows an engine 10 receiving delivery of a plurality ofsubstances (1, 2, . . . , N) as indicated by arrow 8. The varioussubstances may include multiple different fuel blends or otheralternatives. In one example, multiple different substances havingdifferent gasoline and/or alcohol and/or water concentrations may bedelivered to the engine, and may be delivered in a mixed state, orseparately delivered. Further, the relative amounts and/or ratios of thedifferent substances provided to the engine may be controlled by acontroller 6 in response to operating conditions, which may be providedby and/or inferred via sensor(s) 4. Alternatively, or under someconditions, the relative amounts and/or ratios may be determined by thefuel blend added to the vehicle by the customer, and thus may notsignificantly vary during operation.

In one example, the different substances may represent different fuelshaving different levels of alcohol, including one substance beinggasoline and the other being ethanol. In another example, engine 10 mayuse gasoline as a first substance and an alcohol containing fuel such asethanol, methanol, a mixture of gasoline and ethanol (e.g., E85 which isapproximately 85% ethanol and 15% gasoline), a mixture of gasoline andmethanol (e.g., M85 which is approximately 85% methanol and 15%gasoline), a mixture of an alcohol and water, a mixture of an alcohol,water, and gasoline, etc as a second substance. In still anotherexample, the first substance may be a gasoline alcohol blend with alower alcohol concentration than a gasoline alcohol blend of a secondsubstance.

In one embodiment, when using both gasoline and a fuel having alcohol(e.g., ethanol), it may be possible to adjust operating conditions totake advantage of the increased charge cooling of alcohol fuels (e.g.,via direct injection) to provide improved engine performance, because ofthe different properties of alcohol. This phenomenon, combined withincreased compression ratio, and/or boosting and/or engine downsizing,can then be used to obtain fuel economy benefits (by reducing the knocklimitations on the engine), while also allowing engine operation withimproved engine output torque, for example.

Referring now to FIG. 2, one cylinder of a multi-cylinder engine, aswell as the intake and exhaust path connected to that cylinder, isshown. In the embodiment shown in FIG. 2, engine 10 uses a directinjector 66. Further, engine 10 is capable of using a plurality ofdifferent fuel blends. For example, engine 10 may use a mixture ofgasoline and an alcohol containing fuel such as ethanol, methanol, amixture of gasoline and ethanol (e.g., E85 which is approximately 85%ethanol and 15% gasoline), a mixture of gasoline and methanol (e.g., M85which is approximately 85% methanol and 15% gas), etc. Direct injector66 may be used to inject a mixture of gasoline and an alcohol basedfuel, where the ratio of the two fuel quantities in the mixture may beadjusted by controller 12 via a mixing valve, for example. In anotherembodiment, different sized injectors and different fuels may be used.

Internal combustion engine 10, comprising a plurality of combustionchambers, is controlled by electronic engine controller 12. Combustionchamber 30 of engine 10 is shown including combustion chamber walls 32with piston 36 positioned therein and connected to crankshaft 40. Astarter motor (not shown) may be coupled to crankshaft 40 via a flywheel(not shown), or alternatively direct engine starting may be used.

In one particular example, piston 36 may include a recess or bowl (notshown) to help in forming stratified charges of air and fuel, ifdesired. However, in an alternative embodiment, a flat piston may beused.

Combustion chamber, or cylinder, 30 is shown communicating with intakemanifold 44 and exhaust manifold 48 via respective intake valves 52 aand 52 b (not shown), and exhaust valves 54 a and 54 b (not shown).Thus, while four valves per cylinder may be used, in another example, asingle intake and single exhaust valve per cylinder may also be used. Instill another example, two intake valves and one exhaust valve percylinder may be used.

Combustion chamber 30 has an associated compression ratio, which is theratio of volumes when piston 36 is at bottom center and top center.Conventionally, the compression ratio is in the range of 9:1 to 10:1However, when higher octane fuels, fuels with a higher latent enthalpyof vaporization, and/or direct injection is used, the compression ratiocan be raised due to the mitigating effects that octane, latent enthalpyof vaporization, and direct injection have on knock.

Fuel injector 66 is shown directly coupled to combustion chamber 30 fordelivering injected fuel directly therein in proportion to the pulsewidth of signal dfpw received from controller 12 via electronic driver68. While FIG. 2 shows injector 66 as a side injector, it may also belocated overhead of the piston, such as near the position of spark plug92. Such a position may improve mixing and combustion due to the lowervolatility of some alcohol based fuels. Alternatively, the injector maybe located overhead and near the intake valve to improve mixing.Additional fuel injectors may also be used.

Fuel and/or water may be delivered to fuel injector 66 by a highpressure fuel system (not shown) including a fuel tank, fuel pumps, anda fuel rail. Alternatively, fuel and/or water may be delivered by asingle stage fuel pump at lower pressure, in which case the timing ofthe direct fuel injection may be more limited during the compressionstroke than if a high pressure fuel system is used. Further, while notshown, the fuel line may have a pressure transducer providing a signalto controller 12.

Intake manifold 44 is shown communicating with throttle body 58 viathrottle plate 62. In this particular example, throttle plate 62 iscoupled to electric motor 94 so that the position of elliptical throttleplate 62 is controlled by controller 12 via electric motor 94. Thisconfiguration may be referred to as electronic throttle control (ETC),which can also be utilized during idle speed control. In an alternativeembodiment (not shown), a bypass air passageway is arranged in parallelwith throttle plate 62 to control inducted airflow during idle speedcontrol via an idle control by-pass valve positioned within the airpassageway. In the latter alternative, throttle plate 62 is actuated bythe operator of the vehicle, the cable, or other device, between theaccelerator pedal and the throttle valve not shown.

Exhaust gas sensor 76 is shown coupled to exhaust manifold 48 upstreamof catalytic converter 70 (where sensor 76 can correspond to variousdifferent sensors). For example, sensor 76 may be any of many knownsensors for providing an indication of exhaust gas air/fuel ratio suchas a linear oxygen sensor, a UEGO, a two-state oxygen sensor, an EGO, aHEGO, or an HC or CO sensor. In this particular example, sensor 76 is atwo-state oxygen sensor that provides signal EGO to controller 12 whichconverts signal EGO into two-state signal EGOS. A high voltage state ofsignal EGOS indicates exhaust gases are rich of stoichiometry and a lowvoltage state of signal EGOS indicates exhaust gases are lean ofstoichiometry. Signal EGOS may be used to advantage during feedbackair/fuel control to maintain average air/fuel at stoichiometry during astoichiometric, homogeneous mode of operation.

Distributorless ignition system 88 provides ignition spark to combustionchamber 30 via spark plug 92 in response to spark advance signal SA fromcontroller 12.

Controller 12 may cause combustion chamber 30 to operate in a variety ofcombustion modes, including a homogeneous air/fuel mode and/or astratified air/fuel mode by controlling injection timing, injectionamounts, spray patterns, etc. In one example, stratified layers may beformed by operating injector 66 during a compression stroke. In anotherexample, a homogenous mixture may be formed by operating injector 66during an intake stroke (which may be open valve injection). In stillother examples, multiple injections from injector 66 may be used duringone or more strokes (e.g., intake and/or compression). In some examples,a combination of a stratified and homogenous mixtures may be formed inthe chamber. Even further examples may include the use of differentinjection timings and mixture formations under different conditions, asdescribed below.

Controller 12 can adjust the amount of fuel delivered by fuel injector66 so that the homogeneous or stratified air/fuel mixtures orcombinations thereof formed in chamber 30 can be selected to be atstoichiometry, a value rich of stoichiometry, or a value lean ofstoichiometry.

Emission control device 72 is shown positioned downstream of catalyticconverter 70. Emission control device 72 may be a three-way catalyst,particulate filter, NOx trap, or combinations thereof.

Controller 12 is shown as a microcomputer, including microprocessor unit102, input/output ports 104, an electronic storage medium for executableprograms and calibration values shown as read only memory chip 106 inthis particular example, random access memory 108, keep alive memory110, and a conventional data bus. Controller 12 is shown receivingvarious signals from sensors coupled to engine 10, in addition to thosesignals previously discussed, including measurement of inducted mass airflow (MAF) from mass air flow sensor 100 coupled to throttle body 58;engine coolant temperature (ECT) from temperature sensor 112 coupled tocooling sleeve 114; a profile ignition pickup signal (PIP) from Halleffect sensor 118 coupled to crankshaft 40; and throttle position TPfrom throttle position sensor 120; absolute manifold pressure signal MAPfrom sensor 122; an indication of knock from knock sensor 182; and anindication of absolute or relative ambient humidity from sensor 180.Engine speed signal RPM is generated by controller 12 from signal PIP ina conventional manner and manifold pressure signal MAP from a manifoldpressure sensor provides an indication of vacuum, or pressure, in theintake manifold. During stoichiometric operation, this sensor can givean indication of engine load. Further, this sensor, along with enginespeed, can provide an estimate of charge (including air) inducted intothe cylinder. In one example, sensor 118, which is also used as anengine speed sensor, produces a predetermined number of equally spacedpulses every revolution of the crankshaft.

Continuing with FIG. 2, a variable camshaft timing system is shown.Specifically, camshaft 130 of engine 10 is shown communicating withrocker arms 132 and 134 for actuating intake valves 52 a, 52 b andexhaust valves 54 a, 54 b. Camshaft 130 is directly coupled to housing136. Housing 136 forms a toothed wheel having a plurality of teeth 138.Housing 136 is mechanically coupled to crankshaft 40 via a timing chainor belt (not shown). Therefore, housing 136 and camshaft 130 can rotateat a speed substantially equivalent to ½ of the speed of the crankshaft,or other suitable speed. However, by manipulation of the hydrauliccoupling as will be described later herein, the relative position ofcamshaft 130 to crankshaft 40 can be varied by hydraulic pressures inadvance chamber 142 and retard chamber 144. By allowing high pressurehydraulic fluid to enter advance chamber 142, the relative relationshipbetween camshaft 130 and crankshaft 40 is advanced. Thus, intake valves52 a, 52 b and exhaust valves 54 a, 54 b open and close at a timeearlier than normal relative to crankshaft 40. Similarly, by allowinghigh pressure hydraulic fluid to enter retard chamber 144, the relativerelationship between camshaft 130 and crankshaft 40 is retarded. Thus,intake valves 52 a, 52 b, and exhaust valves 54 a, 54 b open and closeat a time later than normal relative to crankshaft 40.

While this example shows a system in which the intake and exhaust valvetiming are controlled concurrently, variable intake cam timing, variableexhaust cam timing, dual independent variable cam timing, or fixed camtiming may be used. Further, variable valve lift may also be used.Further, camshaft profile switching may be used to provide a plurality(usually two) cam profiles which can be selected based on operatingconditions. Further still, the valvetrain may be roller finger follower,direct acting mechanical bucket, electromechanical, electrohydraulic, orother alternatives to rocker arms.

Continuing with the variable cam timing system, teeth 138, being coupledto housing 136 and camshaft 130, allow for measurement of relative camposition via cam timing sensor 150 providing signal VCT to controller12. Teeth 1, 2, 3, and 4 are preferably used for measurement of camtiming and are equally spaced (for example, in a V-8 dual bank engine,spaced 90 degrees apart from one another) while tooth 5 is preferablyused for cylinder identification, as described later herein. Inaddition, controller 12 sends control signals (LACT, RACT) toconventional solenoid valves (not shown) to control the flow ofhydraulic fluid either into advance chamber 142, retard chamber 144, orneither.

Relative cam timing can be measured in a variety of ways. In generalterms, the time, or rotation angle, between the rising edge of the PIPsignal and receiving a signal from one of the plurality of teeth 138 onhousing 136 gives a measure of the relative cam timing. For theparticular example of a V-8 engine, with two cylinder banks and afive-toothed wheel, a measure of cam timing for a particular bank isreceived four times per revolution, with the extra signal used forcylinder identification.

Sensor 160 may also provide an indication of oxygen concentration in theexhaust gas via signal 162, which provides controller 12 a voltageindicative of the O2 concentration. For example, sensor 160 can be aHEGO, UEGO, EGO, or other type of exhaust gas sensor. Also note that, asdescribed above with regard to sensor 76, sensor 160 can correspond tovarious different sensors.

As described above, FIG. 2 merely shows one cylinder of a multi-cylinderengine, and it is understood that each cylinder has its own set ofintake/exhaust valves, fuel injectors, spark plugs, etc.

While not shown in FIG. 2, engine 10 may be coupled to various boostingdevices, such as a supercharger or turbocharger, as shown in FIG. 3. Ona boosted engine, desired torque may also be maintained by adjustingwastegate and/or compressor bypass valves.

Referring now specifically to FIG. 3, an example engine 10 is shown withfour in-line cylinders. In one embodiment, engine 10 may have aturbocharger 319, which has a turbine 319 a coupled to the exhaustmanifold 48 and a compressor 319 b coupled to the intake manifold 44.While FIG. 3 does not show an intercooler, one may optionally be used.Turbine 319 a is typically coupled to compressor 319 b via a drive shaft315. Various types of turbochargers and arrangements may be used. Forexample, a variable geometry turbocharger (VGT) may be used where thegeometry of the turbine and/or compressor may be varied during engineoperation by controller 12. Alternately, or in addition, a variablenozzle turbocharger (VNT) may be used when a variable area nozzle isplaced upstream and/or downstream of the turbine in the exhaust line(and/or upstream or downstream of the compressor in the intake line) forvarying the effective expansion or compression of gasses through theturbocharger. Still other approaches may be used for varying expansionin the exhaust, such as a waste gate valve. FIG. 3 shows an examplebypass valve 320 around turbine 319 a and an example bypass valve 322around compressor 319 b, where each valve may be controlled viacontroller 12. As noted above, the valves may be located within theturbine or compressor, or may be a variable nozzle.

Also, a twin turbocharger arrangement, and/or a sequential turbochargerarrangement, may be used if desired. In the case of multiple adjustableturbocharger and/or stages, it may be desirable to vary a relativeamount of expansion though the turbocharger, depending on operatingconditions (e.g. manifold pressure, airflow, engine speed, etc.).Further, a mechanically or electrically driven supercharger may be used,if desired.

Referring now to FIG. 4, an example fuel delivery system is shown for anexample with a single injector, where the single injector is a directinjector. In this example, a fuel tank 400 is shown for holding a fuel,such as gasoline and an alcohol blend. The fuel tank has an internalfuel pump 402, where the internal fuel pump is a lower pressure fuelpump. A fuel pump 404 is coupled to the lower pressure fuel pump 402 byfuel line 406, where the fuel pump is a higher pressure fuel pump.Higher pressure external fuel pump 404 is coupled to a fuel rail 408having fuel injectors 410 coupled thereto. As noted herein, the fuelpressure at the injector may be adjusted by adjusting parameters such asthe pump operation of one of pumps 402 and/or 404, for example.

Referring now to FIG. 5A, a routine is described for adjusting fuelinjection parameters taking into account an amount of alcohol in thefuel system. In 510, the routine reads an alcohol content of the fuel.The alcohol content of the fuel may be a percent alcohol, mass ratio ofalcohol, volume ratio of alcohol, an amount of oxygen in the fuel, orvarious other indications of an amount of alcohol in the fuel. Theindication may be provided via an alcohol sensor, or may be generatedfrom an estimate based on operating conditions, or combinations thereof.An estimate of alcohol content of the fuel may be formed using feedbackfrom an exhaust gas sensor, in addition to other parameters, such as,for example, a mass airflow amount, a fuel injection pulsewidth, amanifold pressure, and/or others.

Continuing with FIG. 5A, in 512, the routine reads other operatingconditions that may be used to adjust fuel injection timings and/oramounts, such as, for example, engine coolant temperature, feedback froma knock sensor, cylinder air amount, manifold pressure, air chargetemperature, manifold temperature, desired air-fuel ratio, spark timing,atmospheric pressure, and/or various other parameters.

Then, in 513, the routine determines whether to adjust, and if so doesadjust, fuel injection pressure based on a desired engine output torqueand engine speed given the alcohol content of the fuel. Because alcoholsare partially oxygenated, (ethanol is CH₅OH, for example), they liberatea lesser amount of energy (lower heating value) when oxidized duringcombustion than a non-oxygenated hydrocarbon, like gasoline. The mass offuel injected is increased as a function of alcohol content to providethe same combustion energy as gasoline, which requires a greater dynamicrange from the fuel system. The pulse width may be adjusted to providethe desired amount of fuel. However, to handle a wide variety of fuels,including those with high alcohol content, the providing a greateramount of fuel by merely increasing the pulse width may be insufficientwith the additional constraint of maintaining acceptable pulse-to-pulserepeatability at low fuel demand conditions. It is possible to addressdynamic range issues with direct injection when alcohol content of thefuel varies by varying the fuel supply pressure with higher pressures athigher speed and/or torque conditions and lower pressures at lower speedand/or torque conditions.

Continuing with FIG. 5A, in 514, the routine determines a number ofinjections per engine cycle to be performed based on conditions and theamount of alcohol in the fuel. For example, as the amount of alcohol inthe fuel increases, a greater or lesser number of injections for a givenoperating condition (e.g., a given speed/load condition) may beselected. Also, in the case of multiple injections per power cycle, agreater fraction of fuel may injected in an earlier injection as alcoholcontent increases so that there is more time for vaporization.

Then, in 516, the routine determines an injection timing (or timings inthe case of multiple injections per cycle) based on conditions and thealcohol amount of the fuel. For example, injection timing of one or moreinjections may be advanced with increased alcohol in the fuel to takeadvantage of higher latent enthalpy of vaporization of alcohol to allowmore time for vaporization. In one example, the injection timing may beadvanced as a function of alcohol content and also the nature of thealcohol (e.g., ethanol vs. methanol). More injection timing advance maybe used for methanol than ethanol because of its relatively higherlatent enthalpy of vaporization, for example. Also, the timing of theinjections may be adjusted based on the number of injections. In anotherexample, injection timing may be advanced toward the period where thereis pushback into the intake as a function of alcohol content. In thisway, vaporization of the alcohol fuel can be aided by passing by theintake valve (twice, out and in). By cooling the intake system in thisway, the charge density rammed into the combustion chamber can beincreased thereby improving peak torque output of the engine. As such,injection timing may be adjusted based on engine torque and alcoholcontent to improve engine output.

Note that other engine control adjustments may be made based on alcoholcontent of the fuel, such as spark timing, boosting, and/or variousothers. In one example, the controller may increase boost on a variablegeometry turbocharger (or via wastegate control) as a function of theincreased octane in fuel due to the alcohol content. Due to directinjection into the cylinder, the cooling effect of the vaporization ofthe fuel occurs in the cylinder. This can increase the cooling comparedto port injection and allows a greater boost without incurring knock.

In another example, the controller may adjust valve timing to increasevalve overlap and inject fuel having alcohol at least partially duringthe valve overlap period to enhance the charge cooling effect withincreased alcohol in the fuel. For example, intake valve timing may beadvanced and/or exhaust valve timing may be retarded as will bedescribed below with reference to FIG. 5B, for example.

Further still, ignition timing and/or valve timing may also be adjustedin response to an alcohol amount of the fuel.

Various examples of variable injection timing and number of injectionsper cycle are illustrated in FIG. 5B, where the dashed vertical linesindicate intake valve opening and intake valve closing. As one example,the intake valve opening duration may be approximately 248° and theexhaust valve opening duration may be approximately 240°, wherein theintake valve is opened at approximately 10° before top dead center ofthe intake stroke and the intake valve is closed at approximately 58°after bottom dead center of the intake stroke, and the exhaust valve isopened at approximately 50° before bottom dead center of the expansionstroke and the exhaust valve is closed at approximately 10° after topdead center of the intake stroke. It should be appreciated that theabove valve control scenario is just one example and that other suitablevalve timings may be used. Various parameters may affect the adjustmentsshown between the graphs of FIG. 5B, as noted herein, including analcohol amount of the fuel and/or other operating parameters such asalcohol type, fuel injection timing, number of fuel injection pulses,fuel injection supply pressure, boosting, knock detection, temperature,engine starting, or others.

In the first graph (I), a single injection is shown occurring partiallyduring the intake stroke and ending after the close of the intake valve.The injection occurs partially during an open intake valve. In thisexample, the injection is advanced compared to the injection timing inthe second graph (II), which shows both a shorter duration of fuelinjection, and a later timing during a compression stroke. The shorterduration may be to compensate for an increased energy density and loweralcohol content, for example. The third graph (III) shows multipleinjections (two) during the cycle, both during the compression stroke.However, based on alcohol content and/or other parameters, injectionsmay occur during the intake stroke as well as during the compressionstroke as shown by the fourth graph (IV). Further, as shown by comparingthe third and fourth graphs, the relative amount of the injections maybe adjusted based on alcohol content of the fuel and/or otherparameters. Also, the fifth graph (V) illustrates how changes in alcoholcontent of the fuel can affect the duration between injections as well.

The sixth graph (VI) illustrates an example of variable timing, relativeamounts of injection, and timing between injections, being varied inresponse to parameters such as alcohol content of the fuel. Finally, thelast graph (VII) illustrates injection timing using pushback effectswith valve overlap. As noted above, such operation may be used tofurther take advantage of charge cooling/vaporization effects withincreased alcohol content in the fuel to increase torque of the enginewhile reducing knock effects.

Referring now to FIG. 6, a routine 600 is described for determiningdesired engine operation parameters in response to the fuel compositionand driver demand to control engine and/or powertrain torque. Inparticular, routine 600 adjusts the torque of an engine to compensatefor variations in fuel composition.

Specifically, in 610, routine 600 reads various engine and operatingcondition input sensors and parameters, such as engine speed, pedalposition, mass airflow sensor (MAF), fuel alcohol content, etc. Then, in620, the read values may be used to calculate the desired torque. Andthen, in 630 the routine determines various settings for engine and/orpowertrain actuators to provide the desired torque. Additional detailsof one example approach for providing torque control are provided withregard to FIG. 7.

Referring now to FIG. 7, a routine 700 is illustrated schematically fordetermining various engine operating parameters in response to inputvalues in order to provide torque control. Input parameters are showngenerally at 702 and processed to generate the desired outputs showngenerally at 726.

Inputs 702 may include MAF 704, driver demand sensors 706 (e.g., pedalposition detector, gear detector, etc.), crank angle sensor 708, andalcohol content (such as via a sensor 712 or an estimate based on othersensors) as well as other parameters.

In one embodiment, routine 700 may be used to determine a desired torqueat 714. For example, desired torque may be a desired engine torquedetermined as a function of fuel composition and/or engine speed and/ordriver demand. Specifically, desired torque 714 may be determined inresponse to values from the crank angle sensor 708 and driver demandsensors 706. Alternatively, the routine may determined a desired wheeltorque based on driver demand, vehicle speed, and gear ratio, forexample. The desired wheel torque, along with gear ratio and otherparameters may then be translated into a desired engine torque.

Further, in the example where the peak torque, or torque range, of theengine varies with the alcohol content of the fuel, the desired torqueis also based on the amount of alcohol in the fuel. For example, thedriver demand may be scaled by the alcohol content so that maximum pedalposition may correspond to maximum torque, even as the alcohol contentvaries and the maximum torque output varies. In this way, the vehicleoperator is able to obtain peak engine torque from the vehicle under avariety of operating conditions, such as variable alcohol content of thefuel.

Continuing with FIG. 7, from the desired torque, the routine alsodetermines various control settings, such as spark timing in 718 (whichis used to control the spark plug in 730), desired boost in 716 (whichis then used to control the turbocharger adjustment in 728) and desiredthrottle position in 727. Further, the routine also identifies thestoichiometric air-fuel ratio of the fuel blend, which then may be usedas the desired air-fuel ratio for feedback control in 720. For example,from the desired air-fuel ratio, a desired fuel mass is determined in722 and then used to adjust the fuel pulse width of the injector 724,along with feedback from an exhaust gas oxygen sensor.

Referring now to FIG. 8, a routine 800 is described for controllingvehicle operation to accommodate an engine with a variable torque range(such as via a variable peak torque output) that can vary with an amountof alcohol in the fuel. Specifically, in 810, the routine determines thecurrent torque range available based on the alcohol content of the fueland operating conditions. Based on the torque range, various adjustmentsmay be performed in 820, such as:

-   -   adjustment of transmission shift points or other transmission        operation (such as torque converter lock-up, and or clutch        pressure levels and/or profiles) to provide appropriate gear        selection, transmission performance, and engine torque output        (for example, transmission shifting may occur at different pedal        positions to accommodate increased torque output as an amount of        alcohol in the fuel is increased).    -   adjustment of traction control or other vehicle stability        control (such as spark suppression, reduction of fuel supply,        braking the wheels, and/or closing the throttle) to prevent loss        of control of the vehicle when excessive throttle or steering is        applied by the driver.    -   adjustment of diagnostics (such as throttle closure, engine        overheating, etc.) to check for engine component failures.    -   adjustment of engine cooling (such as active air cooling and/or        liquid cooling) to redirect waste heat energy from the engine,        where cooling flow, fan speed, or various others may be        adjusted.

Controlling vehicle operation based on these adjustments may facilitateengine operation at high levels of efficiency and improved performance.

Note that the control routines included herein can be used with variousengine configurations, such as those described above. The specificroutine described herein may represent one or more of any number ofprocessing strategies such as event-driven, interrupt-driven,multi-tasking, multi-threading, and the like. As such, various steps orfunctions illustrated may be performed in the sequence illustrated, inparallel, or in some cases omitted. Likewise, the order of processing isnot necessarily required to achieve the features and advantages of theexample embodiments described herein, but is provided for ease ofillustration and description. One or more of the illustrated steps orfunctions may be repeatedly performed depending on the particularstrategy being used. Further, the described steps may graphicallyrepresent code to be programmed into the computer readable storagemedium in controller 12.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. For example, the above technology can be applied to V-6,I-4, I-6, V-8, V-10, V-12, opposed 4, and other engine types. As anotherexample, various other mechanisms may be used in a system using twodifferent valve profiles for each of the valves in a cylinder, and theselective deactivation of one or more valves to provide the correct flowconditions for compression or auto-ignition combustion. The subjectmatter of the present disclosure includes all novel and nonobviouscombinations and subcombinations of the various systems andconfigurations, and other features, functions, and/or propertiesdisclosed herein.

FIG. 9 schematically demonstrates a marketing approach 900 for promotingthe sale of a vehicle containing an engine capable of operating on aplurality of fuel blends and/or mixtures, such as a flex fuel vehiclehaving an engine with one or more of the above features describedherein. In particular, marketing approach 900 promotes an engine and/orvehicle containing such an engine that may be capable of higher peakengine output torque when operated with increased amounts of alcohol inthe fuel compared with gasoline.

In 910, various avenues of advertisement may be used to promote theengine. Avenues may include a plurality of media forms, such as but notlimited to television, print, news, radio, internet, etc. Advertisementsmay be targeted towards various audiences such as environmentallyconscientious consumers, for example, who also are in need of a vehiclewith high towing capacity, high peak torque, etc. Advertisements mayhave a marketing focus. In one example, advertisements may drawattention to higher torque values available when using a fuel havingincreased alcohol. In another example, advertisements may draw attentionto emissions of such an engine when using a fuel having increasedalcohol. In still another example, advertisements may draw attention toincreased fuel economy available when using a fuel having increasedalcohol. In yet another example, advertisements may draw attention tothe ability of the vehicle to operate with varying levels of alcohol inthe fuel, including gasoline without additional alcohol. For example,the marketing strategy may advertise how improved knock reduction withalcohol-containing fuels, along with boosting, enables improved vehiclerange even when using alcohol-containing fuels. And, combinations of theabove may also be used.

In 920, a vehicle with an engine capable of utilizing alcohol based fuelto achieve improved performance compared with gasoline is sold. It maybe emphasized that the engine may have a combination of properties thatallow for a higher torque with the use of alcohol in the fuel. Forexample, specification sheets may describe direct injection, variableboosting, adjustable spark timing, etc.

Referring now to FIG. 10, a routine 1000 describes one embodiment of amarketing strategy to sell a vehicle with a flexible fuel engine.

In 1020, a public demonstration may be organized to allow public viewingof a vehicle operating on flexible fuels. A public demonstration mayoccur at a car show, for example. In another example, the engine may bedemonstrated in an alternative energy symposium or conference. In yetanother example, a demonstration may occur in a community venue, such asa mall. A plurality of concepts may be demonstrated by the vehicle. Forexample, a monitor may demonstrate torque produced by the engine.Further, torque may be monitored while fuel composition is alsomonitored.

Proceeding with FIG. 10, in 1030, interested consumers may fill out aninformation card for further contact. The card may contain personalinformation such as address, phone number, email address, etc. In oneembodiment, the information card may include the vehicle owners make andmodel. In another embodiment, the information card may includedemographics, such as age, race, gender, etc.

In 1040, a comparative report may be sent to the interested consumer.The report may include information such as price, fuel economy, maximumtorque with varying alcohol content, and/or emissions comparisons. Theinterested consumer thereby has further access to information about flexfuel vehicles. Further, the seller may have contact information from aninterested consumer for future events.

The following claims particularly point out certain combinations andsubcombinations regarded as novel and nonobvious. These claims may referto “an” element or “a first” element or the equivalent thereof. Suchclaims should be understood to include incorporation of one or more suchelements, neither requiring nor excluding two or more such elements.Other combinations and subcombinations of the disclosed features,functions, elements, and/or properties may be claimed through amendmentof the present claims or through presentation of new claims in this or arelated application. Such claims, whether broader, narrower, equal, ordifferent in scope to the original claims, also are regarded as includedwithin the subject matter of the present disclosure.

1. A vehicle system including an engine having a cylinder and combustinga fuel, the vehicle system comprising: a fuel system including a solefuel tank holding a fuel with a variable alcohol content; a directinjection fuel injector coupled to the cylinder, the direct injectionfuel injector coupled to the sole fuel tank and delivering the fuel withthe variable alcohol content to the cylinder; a variable valve timingsystem; an turbocharger coupled to the engine and fluidly coupled to thecylinder, the turbocharger including a wastegate; and a control systemthat varies at least a spark timing of the cylinder and boost amount ofthe turbocharger based on an alcohol content of the fuel, the controlsystem further operating the engine to produce increased peak torqueoutput when the alcohol content is increased, at least during onecondition, the control system further adjusting cylinder valve timingvia the variable valve timing system responsive to the alcohol content.2. The vehicle system of claim 1, wherein a desired torque of the engineis based on an amount of alcohol in the fuel, the desired torque scaledby the amount of alcohol so that maximum pedal position corresponds topeak torque even as peak torque output of an engine varies.
 3. Thevehicle system of claim 1, wherein the control system adjuststransmission shifting in response to variation of the alcohol content ofthe fuel to account for the increased peak torque output.
 4. The vehiclesystem of claim 1, wherein the control system adjusts engine cooling inresponse to variation of the alcohol content.
 5. The vehicle system ofclaim 1, wherein the control system adjusts traction control operationin response to variation of the variable alcohol content.
 6. The vehiclesystem of claim 1, wherein the control system varies spark timing andboost in response to both the alcohol content and knock sensor feedbackin coordination.
 7. The vehicle system of claim 1, wherein the controlsystem varies timing between multiple injections based on the alcoholcontent.
 8. The vehicle system of claim 1, wherein the control systemincludes varying turbocharger boost via the wastegate.
 9. A method forcombusting fuel in an engine, comprising: directly injecting a fuelhaving a varying amount of alcohol to a cylinder; varying a spark timingof the cylinder, a boost amount provided to the cylinder, and aninjection timing as an alcohol content of the fuel varies, wherein adesired torque related to an accelerator position is scaled as a peaktorque of the engine varies.
 10. The method of claim 9, furthercomprising adjusting a number of fuel injections per cylinder cyclebased on alcohol content of the fuel.
 11. The method of claim 9, furthercomprising adjusting cylinder valve timing based on alcohol content ofthe fuel.
 12. The method of claim 9, further comprising directlyinjecting fuel with a first and second injection during a cylindercycle, adjusting a timing between injections based on alcohol content ofthe fuel.
 13. The method of claim 12, wherein adjusting the boost amountincludes adjusting a turbocharger wastegate.
 14. A system for an enginehaving at least a cylinder and combusting a fuel, the system comprising:a direct injection fuel injector for directly injecting said fuel tosaid at least a cylinder; a variable cam timing system; an intake chargeboosting device coupled to the engine and fluidly coupled to thecylinder; and a control system for varying at least a spark timing ofthe at least a cylinder, a boost amount of said intake charge boostingdevice, and cam timing, as an alcohol content of said fuel directlyinjected to said at least a cylinder varies, said control systemoperating the engine to produce increased peak torque output when saidalcohol content is increased, at least during one condition, where theboost amount is increased and the spark timing is advanced withincreased alcohol content of said fuel for at least said one conditioncompared with lower alcohol content operation.
 15. The system of claim14 wherein said control system determines alcohol content of said fuelbased on at least exhaust gas sensor information.
 16. The system ofclaim 14 wherein a desired torque of said engine is based on an amountof alcohol in said fuel, said desired torque scaled by the amount ofalcohol so that maximum pedal position corresponds to peak torque evenas peak torque output of the engine varies.
 17. The system of claim 14wherein said control system further adjusts transmission shifting inresponse to variation of said alcohol content to account for saidincreased peak torque availability.
 18. The system of claim 14 whereinsaid control system further adjusts engine cooling in response tovariation of said alcohol content.
 19. The system of claim 14 whereinsaid control system further adjusts traction control operation inresponse to variation of said alcohol content.